Real time monitoring of tool wear using multiple modeling method

Real time monitoring of tool wear in machining operations is very crucial in order to prevent tool failures, increase machine utilization and decrease production cost in an automated manufacturing environment. In general the price of the tool is relatively low, but the failure can cause incomparably higher production cost. Over the years, a wide variety of tool condition monitoring (TCM) techniques has been developed based on sensor signals such as cutting forces, acoustic emission and vibration. In this paper, a real time monitoring technique based on multiple modeling method is presented for drilling operations which is one of the most widely used manufacturing operations. The multiple modeling method utilizes cutting forces (thrust and torque) collected during the drilling operation and classify these forces using Hidden Markov Models (HMM) to determine wear status of the drill bit. Experimental results have been presented in order to demonstrate the effectiveness of the proposed method.